No Drop in VAP Rates, Study Contends

Diana Swift

November 21, 2016

Contrary to previously reported numbers from the Centers for Disease Control and Prevention (CDC), ventilator-assisted pneumonia (VAP) rates have not declined, but have remained near 10% since 2005, according to data from the Medicare Patient Safety Monitoring System (MPSMS).

MPSMS-measured VAP incidence, based on a review of hospital charts of elderly patients in intensive care units, was 10.8% (95% confidence interval, 7.4% - 14.4%) during 2005 to 2006 and 9.7% (95% confidence interval, 5.1% - 14.9%) during 2012 to 2013, report Mark L. Metersky, MD, a professor of medicine and director of the Center for Bronchiectasis Care at UConn Health Pulmonary/Critical Care in Farmington, Connecticut, and colleagues in a research letter published online November 11 in JAMA.

In contrast, data from the CDC's National Healthcare Safety Network (NHSN) have shown declines in VAP rates of 71% and 62% in medical and surgical intensive care units, respectively, between 2006 and 2012.

"The most likely explanation for the discrepancy is thought to be bias in reporting to CDC by the hospitals," Dr Metersky told Medscape Medical News.

He noted that whereas he and his coauthors discuss other possible reasons in the letter, including differences in definitions, hospitals, or patient groups, "they are very unlikely to explain such a huge discrepancy."

He continued: "VAP remains a common problem, and more specifically, our results suggest we have made no progress over the last decade in decreasing its frequency. This is important, given its cost in terms of deaths, morbidity, cost and resource use.... Because VAP is not going away, we need more research into how to prevent and treat it."

Charles S. Dela Cruz, MD, PhD, an associate professor in the Section of Pulmonary, Critical Care and Sleep Medicine and director of the Center of Pulmonary Infection Research and Treatment at Yale University in New Haven, Connecticut, who was not involved in the study, agreed the steady 10% VAP rate remains a problem.

"Because of this, we should not be complacent in our efforts to reduce VAP," Dr Dela Cruz told Medscape Medical News. "If the message is clearly received that we really have not made any major headway at reducing VAP, hospitals and practitioners will make better efforts at properly tracking VAP rates and implementing measures to reduce them."

MPSMS VAP Definition Constant

For the current analysis, Dr Metersky and colleagues reviewed MPSMS data on a representative sample of more than 86,000 critically ill patients treated at 1330 US hospitals between 2005 and 2013. They limited their sample to patients who required at least 2 days' ventilation in intensive care units and who had one of four conditions: acute myocardial infarction, heart failure/pulmonary edema, pneumonia, and major surgery.

Among patients included in the MPSMS data, 1856 met the inclusion criteria. The mean age of patients was 78.6 years, 54.9% were women, and 87.3% were white. Many had comorbidities such as cancer, cerebrovascular disease, diabetes, renal disease, and chronic obstructive pulmonary disease.

The investigators divided the cohort into four time intervals, 2005 to 2006, 2007 to 2009, 2010 to 2011, and 2012 to 2013. (Data for 2008 were not available because of a lack of federal funding.)

Although the investigators report a small dip in VAP rates in the 2007 to 2009 period, to 7.5%, it was not significantly different from the other three intervals: 10.8% in 2005 to 2006, 10.4% in 2010 to 2011, and 10.2% in 2012 to 2013.

The authors note that the definition of VAP used was consistent throughout the study. "Determination of VAP required all of the following beginning 2 or more days after initiation of mechanical ventilation: chest radiograph with a new finding suggesting pneumonia, physician diagnosis of pneumonia, and an order for antibiotics to treat pneumonia," they write.

"Surveillance is tricky, so we need more attention paid to how best to track VAP rates," Dr Metersky told Medscape Medical News.

Dr Dela Cruz agreed that several factors are driving the differences between these new data and those reported from NHSN data. "Strict and varying VAP measure definitions and the hospital reporting mechanisms possibly contributed to the differences in rates," he said.

The dichotomy underscores mounting concern that traditional surveillance definitions may be unreliable, Dr Metersky and colleagues write. "The ongoing risk to patient safety represented by VAP supports the NHSN's decision to explore more objective surveillance targets."

Pointing to anecdotal reports of steep declines in VAP rates and the parallel reports of declining rates by the CDC, Dr Metersky said, "Skeptical experts suggested that doctors were declining to document VAP in the charts due to public reporting, and that perhaps due to incentives being paid for low VAP rates, some were 'gaming' their documentation."

However, the MPMSM definition is based on physicians' chart notes documenting diagnoses of VAP. "Without the doctor saying that there was VAP, the case did not qualify as VAP," Dr Metersky said. "This strongly suggests that clinicians are not gaming the diagnosis of VAP. If there is gaming going on, it is not by the physician at the bedside."

Dr Dela Cruz does not suspect any deliberate bias for hospitals to report a decline. "We just have to have more objective measures of VAP in our [intensive care units], so we can provide improved care for our patients," he said.

He continued, "Hospitals need to invest in programs that help prevent VAP. This is especially important as our patient population continues to live longer with more complex medical problems, and our options for treating VAP may be limited one day by antibiotics resistance."

This study was supported by the Agency for Healthcare Research and Quality of the US Department of Health and Human Services. The study authors and the commentator have disclosed no relevant financial relationships.

JAMA. Published online November 11, 2016. Full text

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